The heart of a computer is a magnetic hard disk drive (HDD) which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The volume of information processing in the information age is increasing rapidly. In particular, HDDs have been desired to store more information in its limited area and volume. A technical approach to this desire is to increase the capacity by increasing the recording density of the HDD. To achieve higher recording density, further miniaturization of recording bits is effective, which in turn typically requires the design of smaller and smaller components.
The further miniaturization of the various components, however, presents its own set of challenges and obstacles.
The Damascene design process is used in forming write poles. It is usually preferred that the Damascene design process includes a nonmagnetic metal layer, which is usually deposited conformally across the wafer and into the Damascene trench. Such metal layer will functionally be part of the gap separating the main pole and the surrounding shield.
However, due to the extremely small dimensions of the Damascene trench and various processing constraints such as process temperature requirements, there are very few process choices for creating such a metallic layer, one option including Atomic Layer CVD Ru deposition (ALCVD Ru). It is critically important that this Ru layer provides, correct material interfacial microstructure to promote CoFe growth with high permeability for high data rate. Much work has been put into “seed” process, either for CoFe growth (such as the use of NiCr as seed) or seeding for Ru (such as Ta or NiCr). There may be limitations with the seed approach, which usually relies on vacuum deposition techniques.
Moreover, a favorable seed for CoFe growth depends on many factors such as deposition parameters, substrate type and condition. For cases where film growth is inside a constrained volume such as a Damascene trench, film growth conditions may be completely different from those out on an open surface, because these techniques not only rely on chemical potential differences but also on vectorial momenta of the reactive species. For at least the forgoing reasons, improvements in the development of write pole formation would be very beneficial.